Burger King's Bacon King burger serves up 1,147 calories, 79 grams of fat, 30 grams of saturated fat, and 2,153 milligrams sodium. That's more total fat, saturated fat, and sodium than you should have in a whole day – and it doesn’t even include fries or a soda.

You can find the same kind of health-destroying excess on the menus at scores of other fast food places. But most people don't realize just how overstuffed with calories, fat, and sodium that food is.

A new study published in the journal BMJ found that adults' fast food orders at McDonald's, Burger King, Subway, Wendy's, KFC, and Dunkin' Donuts averaged 836 calories, even though the customers thought they dished up around 660 calories.

Teens were even more in the dark. While their orders averaged 756 calories, they thought they only contained around 500 calories.

A whopping 45% of 20- to 39-year-olds and almost 38% of people ages 40 to 59 eat fast food on any given day. If that's you, it's time to get hip to what's packing fat on your hips and belly, putting plaque in your arteries, and inflaming your joints.

The Food and Drug Administration requires large restaurant chains to post calorie counts on their menus and make information about total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrates, sugars, fiber, and protein available.

Slow down enough to look into what you're about to put in your mouth — and ask yourself if you want to take the fast-food track to obesity, heart disease, dementia, and other chronic ailments.

Then drive on through without stopping.